Evolving Views of Regoliths on Airless Planetary Bodies: The Moon as a Paradigm

The formation and evolution of regolith, including soil and dust, on airless bodies presents a different collection of processes to bear than those present on Earth. Meteorite and particularly micro-meteorite impacts provide the majority of the energy that causes several processes of weathering and erosion. We now understand, he writes modestly, the comminution, agglutination, vaporization, and deposition causing the formation of the lunar soil, and these have become the paradigms for all airless bodies – or at least a starting point for inquiry. During the last few years, the discovery of OH and HOH on and In the Moon has brought forth an entirely new set of parameters necessary to explain their presence on the Moon – now even asteroids and Vesta – origins that are both exogenic and endogenic. Here again, the study of Apollo and lunar-meteorite samples, coupled with well-designed experiments and modeling, will form the basis for our extensions of lunar knowledge into the airless bodies of the Solar System.